The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Gerotor pumps have wide range of application. These devices are used as compressor for air conditioner, hydraulic motor to drive mechanical systems, pump to deliver oil to lubricate the internal components in motion of the engine, pump in the automatic transmission to provide hydraulic power to actuate the clutch or dual clutch systems, just to name a few. However, pursuit to increase volumetric efficiency of gerotor pumps as well as to prevent or mitigate galling and gauging of pump components during operation has never come to an end.
Gerotor pump includes a housing member, an outer rotor and an inner rotor operatively engaged to form a rotor set disposed within the housing member. A thrust plate and a pressure plate within the housing member define an axial space where the rotor set is enclosed and driven by an input shaft. During operation, teeth of the inner rotor travel over a conjugate inner surface of the outer rotor to form expanding volume chambers for fluid intake, and contracting volume chamber for providing pressurized fluid output. A clearance between the inner rotor and the outer rotor is necessary to allow the inner rotor to rotate within the outer rotor; however, fluid leakage may also result due to the clearance and result in a lower volumetric efficiency. Pressure capability may also be reduced as the clearance between inner and outer rotor grows arising out of normal wear and tear but without means of compensation.
The rotor set rotates inside the space defined by the thrust plate and the pressure plate. It is desirable that axial ends of the outer rotor and inner rotor make tight sealing engagement with adjacent axial end surfaces of the thrust plate and pressure plate to avoid fluid leakage. A tight sealing engagement, however, may result in undesirable galling and gauging of the rotors and the plates, resulting in device damage. Fluid may be pumped to the mechanical clearances between the rotor set and the thrust and pressure plates to provide lubrication to prevent the galling and gauging of component.